1. Field of the Invention
The present invention relates generally to powered excavation equipment, and more particularly to an attachment for skid loaders, front end loaders, and similar powered machinery. The present excavation attachment is installed in place of the conventional bucket, and serves as a distal fulcrum for lifting, prying, or moving solidly secured objects and hard ground, greatly reducing the likelihood of lifting the opposite end of the machine from the ground when great force is applied. A pair of fixed teeth extend from the attachment to provide localized force in prying and/or breaking up hard materials. In another embodiment, additional opposed and movable teeth are provided opposite the stationary teeth of the attachment, for the attachment to serve as a grapple.
2. Description of the Related Art
Powered excavation machinery, such as skid loaders, front end loaders, etc., are universally equipped with powerful hydraulic units for operating their loader buckets. A hydraulic pump operated by the engine of the machine provides hydraulic fluid under extremely high pressure to the hydraulic cylinders connected to the loader bucket, which are in turn selectively actuated to operate the bucket through its range of motion.
The mechanical force which may be developed by the hydraulic system of such machines can actually exceed the weight of the machine, or at least a large percentage of the weight of the machine. Generally, the weight of the machine distributed opposite the load bucket is somewhat greater than the weight imposed by any load likely to be lifted by the load bucket. However, oftentimes the load bucket (or teeth or tines, if so equipped) is used to pry or force a particularly difficult object loose from the ground, e.g., a large slab of concrete, a tree stump, a buried concrete anchor, etc. When this occurs, the load imposed can greatly exceed the weight of any mass which might be contained in the bucket, and can result in the machine rotating about the fulcrum defined by the wheels closest to the load bucket, lifting the opposite wheels clear of the underlying surface.
This problem would be easily resolved if due only to an excessively heavy mass in the bucket, by dumping some of the mass, but as noted above, the volume of the load bucket is generally not sufficiently large as to hold sufficient weight to produce this overcenter reaction. Such a reaction is almost always due to a stubborn object imbedded in the ground, with the anchoring force adding to the weight of the object to resist lifting by using the load bucket. There is generally no recourse to this problem, other than to attempt to break up the object into smaller pieces, or perhaps get a second machine on the opposite side (if possible), to distribute the load among the two machines rather than having a single machine carry the entire load.
Accordingly, a need will be seen for some means for lifting highly resistant loads from their anchor points, using a powered excavating machine. The present invention responds to this need by means of a generally cylindrical attachment installed transversely in place of the conventional load bucket of a skid loader, end loader, or other powered excavating machine. The device includes a series of (two, or perhaps more) teeth or tines extending generally radially therefrom, for lifting and prying particularly stubborn objects and/or hard ground from the underlying surface or substrate. The present attachment is used by rotating it to orient the teeth somewhat downwardly, and lowering the device (and perhaps driving the machine toward the object) to drive the tines or teeth into or below the object. The attachment is then lowered to the ground and the tines rotated upwardly, to lift the object. The cylindrical shape of the attachment acts as a fulcrum considerably closer to the lifting tines or teeth than the closer road wheels of the machine, thereby providing significantly greater leverage for levering and forcing the object from the underlying surface.
In another embodiment, a set of additional hydraulically actuated tines or teeth may be provided, generally opposed to the first set of fixed teeth. The fixed and movable teeth may be used as a grapple, for lifting difficult to move objects from the underlying surface.
A discussion of the related art of which the present inventor is aware, and its differences and distinctions from the present invention, is provided below.
U.S. Pat. No. 2,608,772 issued on Sep. 2, 1952 to Royal B. Laird, titled "Dual Purpose Ground Working Implement," describes a cylindrical drum disposed transversely from a conventional three point hitch on the back of a tractor or the like. The drum includes a series of different earthworking implements extending from its surface. The drum can be rotated about its transverse axis, with a remotely operated pin serving to lock the drum in a predetermined desired position. The operator releases the lock pin and drives the tractor to roll the drum to position the desired implement downwardly according to the earthworking operation desired, and engages the pin to lock the drum in place. No hydraulic operation is provided, and the device does not act as a fulcrum or provide additional leverage for the machine, but rather merely serves as a multiple purpose earthworking implement.
U.S. Pat. No. 2,837,844 issued on Jun. 10, 1958 to Richard L. Launder, titled "Rooter Attachment For Bulldozers Or The Like," describes a pair of tines or teeth which are removably attachable vertically across the face of the blade of the machine. The teeth extend below the lower edge of the blade, to dig into the underlying surface or substrate for removing roots and similar operations. The Launder attachment teaches away from provision of a fulcrum closer to the earthworking components (tines, etc.), as the blade cannot be rotated upwardly to the extent that a loader bucket can be, and thus cannot provide the fulcrum point provided by the present attachment in concert with an excavating machine.
U.S. Pat. No. 3,596,996 issued on Aug. 3, 1971 to Jack D. Carter, titled "Method And Apparatus For Using A Back Hoe Bucket As A Frozen Ground Ripper," describes a pair of teeth attachable to the back side of a back hoe bucket. The teeth are manually extendible below the bucket for ripping operations, or may be retracted for normal use of the bucket as a scoop or for lighter breaking operations. The Carter arrangement cannot provide any form of fulcrum for the teeth, as they extend essentially below and behind the bucket, between the bucket and nearest wheels.
U.S. Pat. No. 3,778,111 issued on Dec. 11, 1973 to Pio A. Ciofani, titled "Ripper Tooth Attachment For A Backhoe," describes a hook installed to the back of a backhoe bucket for use in breaking up and ripping materials, e. g., concrete slabs, etc., when the bucket is curled under to extend the tooth or hook therebelow. The relationship between the tooth and the bucket precludes use of the bucket as a fulcrum for the tooth, as the tooth or hook is oriented back beneath the bucket, rather than extending outwardly away from the bucket, as in the orientation of the teeth or tines to the drum of the present attachment.
U.S. Pat. No. 3,959,900 issued on Jun. 1, 1976 to Dieter G. Luck, titled "Implement Assembly For Hydraulically Operated Excavators," describes a relatively complex scoop and ripper tooth combination, each independently hydraulically positionable relative to the other. The back of the scoop is disposed upwardly, with no structure disposed between the ripper and the remainder of the machine to rest on the surface for acting as a fulcrum.
U.S. Pat. No. 3,975,844 issued on Aug. 24, 1976 to Rueben C. Olson, titled "Digger Tooth Means For Front Loader Buckets," describes a bucket having an arcuately movable toothed lower forward edge, for use in scarifying operations and where a tooth equipped bucket is of value. The toothed edge extends on arms pivoted at the lower rear of the bucket, and is selectively actuated by a hydraulic cylinder. The only way the Olson device could work in prying loose or lifting an object, would be to rest the bucket on the underlying surface and actuate the hydraulics to raise the toothed edge. The bucket itself, with its heavy duty hydraulics, would not be moved during this operation. However, Olson does not use the heavy hydraulics associated with bucket operation for his movable toothed edge, as the edge need only be moved into and out of position as desired. In contrast, the present system relies upon the conventional heavy duty hydraulics for tilting the bucket (or rather, the present excavation attachment, when installed) to rotate the teeth of the present device, with the cylindrical body of the device serving as a fulcrum.
U.S. Pat. No. 3,999,315 issued on Dec. 28, 1976 to John C. Nye, titled "Adjustable Attachment For A Backhoe," describes an arcuately selectively positionable elongate tooth attachment. The device relies upon mechanical positioning and locking in place, rather than by hydraulic means. No fulcrum is disclosed for providing increased leverage for the device, nor is any opposite structure disclosed for using the device as a grapple.
U.S. Pat. No. 4,541,664 issued on May 1, 1979 to Nicholas Maura, titled "Ripper Attachment For Backhoe Or Front End Loader," describes a multiple tooth attachment immovably bolted into the otherwise conventional bucket of the machine. The teeth extend to the front of the bucket, but are spaced above the lower forward edge of the bucket. This enables material dislodged by the teeth, to fall into the bucket. In contrast, the present excavation attachment comprises a closed cylinder configuration, with the extended tines or teeth being welded to the exterior surface of the cylinder. The cylindrical surface of the present attachment provides a far better fulcrum than the conventional bucket of the Maura assembly, for using the teeth to lift and dislodge objects.
U.S. Pat. No. 4,327,509 issued on May 4, 1982 to Rufus C.
Bean, titled "Ripper Tooth Attachment For A Back Hoe," describes a hydraulically actuated set of teeth which are pivotally mounted above the bucket. Bean recognizes the problem of leverage with relatively elongate boom structures in backhoes, end loaders, and the like, but responds to the problem with an entirely different, and more complex, solution. Bean rests the machine bucket on the underlying surface, and then hydraulically actuates the teeth to perform the dislodging operation. In contrast, the teeth of the present attachment are permanently and immovably affixed to the cylindrical body of the device, with no other hydraulics being required. The operator need only actuate the controls as in "curling" the bucket, to lever the teeth around the fulcrum defined by the lower portion of the cylinder.
U.S. Pat. No. 4,333,250 issued on Jun. 8, 1982 to Joe W. Henderson, titled "Multi-Purpose Attachment For Vehicles," describes a bucket or scoop which is removably attachable to the back of a small garden tractor or the like by a three point hitch. The device has a few different positions, which may be selected and locked into place by an upwardly extending handle which is manually operated by the operator of the tractor. The device may be rotated about its lateral axis to turn the open side upwardly for use as a container or scoop, or rotated to dispose one open edge downwardly for use as a scraper blade. However, Henderson does not provide any teeth or tines for his device, nor does he provide any means of lifting or lowering the device nor of rotating the device by means of hydraulic power, as provided by the present invention.
U.S. Pat. No. 4,618,005 issued on Oct. 21, 1986 to Douglass G. Tower, titled "Orientable Ripper," describes a rotatable transverse arm having a tooth or tine extending from the distal end thereof. The arm may be rotated hydraulically to adjust the angle of the tooth as desired, for ripping operations. No other structure for placement upon the underlying surface is disclosed, for providing a fulcrum for the ripping tooth of the Tower U.S. Patent. The device is primarily intended for attachment to the blade arm ("bull arm") of a bulldozer, rather than to the scoop or bucket of an end loader, skid loader, or similar earthworking machine.
U.S. Pat. No. 4,749,048 issued on Jun. 7, 1988 to Joseph L. Kelly, titled "Ripper Attachment For Skid Steer Loaders," describes a tooth extending downwardly from a triangulated frame, which is in turn secured to the conventional lift arms of a skid steer loader. No fulcrum is provided by Kelly for his ripper attachment, nor is any hydraulic operation provided other than by the conventional lift arms of the skid steer device. The ripping tooth of the Kelly device is oriented downwardly, and cannot be used for lifting or dislodging an object in an upward direction, as provided by the present attachment. Thus, Kelly does not require any form of fulcrum for his attachment, as use of the device would tend to lift the nearest wheels, rather than applying more downward force to them, as in a lifting operation with a conventional end loader.
U.S. Pat. No. 4,845,867 issued on Jul. 11, 1989 to Allan J. Albrecht, titled "Triple-Purpose Attachment," describes a hydraulically powered, auxiliary arm having ripping teeth at its distal end. The arm is secured to or immediately adjacent the upper edge of the loader bucket of an excavating machine, and serves as a scarifying or breaking device as well as acting as a grapple in combination with the bucket as desired. As the device is mounted above the bucket, it cannot use the bucket as a fulcrum for levering objects from the underlying surface, as provided by the present invention. Moreover, the Albrecht device works against the existing bucket as a grapple, rather than against one or more teeth or tines extending from a common element (e. g., the cylinder of the present attachment).
U.S. Pat. No. 6,023,863 issued on Feb. 15, 2000 to Steven D. Mahin, titled "Frost Hook Attachment For Backhoe," describes a link for attaching an underslung frost hook beneath a backhoe bucket. The frost hook is immovably affixed relative to the bucket, with the two components moving in unison with one another when the bucket is articulated; no grappling or grasping means is provided between the hook and the bucket. As the hook is disposed in front of and below the bucket when the bucket is in its folded or "curled" position, the device cannot utilize the bucket as a fulcrum for lifting or prying objects from the underlying surface, as provided by the present excavating attachment. Moreover, as the hook is immovably affixed relative to the bucket, it cannot be used as a grappling device, as provided in at least one embodiment of the present invention.
Finally, British Patent Publication No. 2,083,110 published on Mar. 17, 1982 to Trevor R. Salmon, titled "Ripper Attachment For Excavator," describes an assembly which is quite similar to that described immediately above in the '863 U.S. Patent to Mahin. The same points of difference noted above between the Mahin '863 U.S. Patent and the present invention, are seen to apply here as well.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus, an excavation attachment for powered loader solving the aforementioned problems is desired.